Safety device for elevators.



Patented Feb. I3, |900. J. FLETCHER.

SAFETY DEVICE FUR ELEVATORS.

(Application led Sept. 14, 1899.) (No Model.) 2 Sheets-Sheet l.

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No. 643,597. Patented Feb. I3, |900. J. FLETCHER.

SAFETY DEVICE FQB ELEVATORS.

Z-Sheets-Sheet (Application led Sept. 14, 1899.) (No Model.) v

FIC-)-3 .TOI-IN FLETCHER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OFTHREE- EIGHTHS TO HARRY W. SPROSON, OF SAME PLACE.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 643,597, dated February13, 1900.

Application filed September 14,1899. Serial No. 730,428. (No model.)

To all whom, it may concern:

Be it known that I, JOHN FLETCHER, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented a certain new and useful Safety Device forElevators, of which the following is a specification, reference beinghad therein to the accompanying drawings.

This invention relates to elevators, and has particular reference tosafety devices used in connection with the cars of passenger and freightelevators and also upon mine cars, cages, or lifts; and one object ofthe invention is to provide, in connection with an elevater-car of anyof the types above mentioned, simple, reliable, and effective meanswhereby in the event of the main hoisting-cable breaking the safetydevices will be thrown immediately into operation, catching or grippingthe guides at opposite sides of the shaft, and thereby preventing thecar from falling. In connection with the safety device guides and shoesof novel construction are employed and two independent sets of devicesare brought into play for the purpose of throwing the safety appliancein to operation, thereby insuring the engagement of such appliance withthe guides.

Other objects and advantages of the invention will appear in the courseof the ensuing description.

The invention consists in certain novel features and details ofconstruction and arrangement of parts, as hereinafter fully described,illustrated in the drawings, and incorporated in the claims.

In the accompanying drawings, Figure 1 is a sectional elevation showinga sufficient portion of an elevator-car and the guides therefor toillustrate the application of the improvements thereto. Fig. 2 is avertical sectional view taken at right angles to Fig. 1 and-lookingtoward one of the double-faced rack-bars, showing also the dogs and aportion of their operating mechanism. Fig. 3 is a vertical transversesection through one of the guides,

lshowing the manner of combining the several sections thereof. Fig. 4 isa horizontal crosssection through the same, showing also a sectionalview of one of the shoes.

Similar numerals of reference designate corresponding parts in all thefigures. Y

The car to which the improvements are ap= plied may be of any ordinaryor preferred construction, l designating the sides or upright portion ofthe car, 2 the floor, and 3 the stationary cross-head by means of whichthe car is ordinarily suspended from the cable, indicated at 4t.) In thepresent instance, however, and in carrying out the presentimprovementsan independent movable cross-head 5 is located above the stationarycross-head 3 and capable of movement toward and away from saidstationary cross-head.

Mounted upon the end portions of the movable cross-head are sleeves 6,which receive the upper ends of a pair of rods 7, the said rodsextending downward through the car and terminating near the floorthereof. The rods 7 are arranged as close to the sides of the car aspracticable and preferably extend downward through openings 8 in theseats 9, where they enter housings 10, preferably of cylindrical form,arranged within and beneath and concealed by the seats 9. Each housingor cylinder 10 is provided with a cap 11, firmly secured thereto, andwithin each cyl'nder is arranged one or more springs 12, preferably ofrubber, although it is within the scope of this invention to substitutefor the rubber springs one or more spiral springs. The springs 12 areinterposed between the cap 11 and a nut 13, threaded upon thelower endof the rod. A jam-nut 14 isV also placed on the threaded end of the rod7 and turned up against the nut 13 to prevent the latter from workingloose. It will thus be seen that the expansion of the springs 12 tendsto draw downward the rods 7, and on vaccount of said rods beingconnected rigidly at their upper ends to the movable cross-head thelatter is at the same time drawn downward toward the stationarycross-head 3, the object of which will hereinafter appear. 95

The main hoisting-cable .tis provided with a shackle 15, which connectsdirectly with the movable cross-head at the point 16, and it will now beunderstood that the weight of the car and the load is suspended entirelyfrom the upper movable cross-head through the medium of thesupporting-rods 'Z and the IOO springs 12, acting in conjunction withthe housings or cylinders within which the springs are located. Byreason of this arrangement the springs 12 are normally compressed.\Vl1en,however,the cable t breaks, the springs l2 expand, with theresult above set forth.

In connection with the construction above described l employcounterbalance-cables 17 and 1S, which run over suitable pulleysadjacent to the elevator-shaft and have applied thereto the usualweights for eounterbalancing the elevator. One of these cables 17 passesdownward through the movable cross-head and around the grooved pulley19, journaled centrally on the stationary cross-head 3, and thenceupward obliquely, whereitis attached at its extremity to the movablecross-head at the point 20. The other counterbalance-eable 18 passesdownward through the movable cross-head, under the pulley 19, andobliquely upward in the opposite direction, where it connects at thepoint 21 with the movable cross-head. From this it will be seen thatupon breakage of the cable 4, as the elevatorcar begins to descend, thetendency of the counterbalance-weights is to uphold the cables 17 and18, with the result that said cables operating around the pulley 19 andupon the movable crosshead will draw the latter downwardA toward thestationary cross-head, the mechanism being utilized for the same purposeas the springs and supporting-rods hereinabove described. Thus twoindependent sets of devices are used for moving the upper cross-headdownward toward the stationary cross-head.

Mounted upon each side of the elevator adjacent to the guides 22 is apair of clutchdogs 23, each of which is fulcrumed intermediate its ends,as at 2t, on one of the horizontal beams 25 of the car or upon any otherconvenient support. These dogs are provided with pointed engagingportions 26, facing toward each other and located on opposite sides ofthe guide 22. Connected to the outer ends of said dogs are rods 27,which extend upward to and connect pivotally with the movable cross-head5 at the points 2S. Each of the guides 22 is provided at opposite sideswith oppositely-projecting rack-bars having teeth 29, with which thedogs 23 are adapted to simultaneously engage. The dogs incline downwardfrom their outer toward their inner or engaging ends and are normallyheld with their engaging portions out of contact and out of engagementwith the teeth 29 of the double rack-bar. Vhen, however, the movablecross-head is drawn toward the stationary cross-head, the dogs 23,through the medium of the connecting-rods 27, are'rocked upon theirfulcrums and their engaging ends thrown instantly into engagement withthe opposite faces of the raekfbar, thus im mediately bringing the carto a stop.

The combined guide and rack-bar is preferably composed of threesections, 30 designating the inner or main section, 3l the outersection, and 32 the intermediate section,which extends laterally beyondthe sides of the seetions 30 and 31, the teeth 29 being formed in saidprojecting portions. The several seetions of the combined guide andrack-bar are secured together by bolts orothersuitablc fasteners. Thecar is provided at suitable points with shoes 34, which are shown inseetion in Fig. 4. Each shoe comprises a body portion of a thicknessequal to the distance from the inner to the outer surfaces of thecombined guide and double rack-bar, and said shoe is provided in itsbody portion with a transverse opening 35 to receive the guide and alsowith oppositely-located grooves or recesses 36 to receive the teeth 29of the rackbar. By this arrangementoppositely-located shoulders 37 areprovided 0n the shoe, which coperate with the opposite side edges 38 ofthe teeth 29, by means of which the shoe and the guide are maintained inproper sliding engagement with each other, and the withdrawal or escapeof the shoe from the guide is impossible. Each shoe is also providedwith suitable ears or anges 39, having openings 40 to receive bolts orother suitable fastenings, by means of which the shoe is attached to theside of the car.

ln mining-cars or freight-elevators, where no seats are employed, thehousings or cylinders l0, in which the springs are contained, may besecured to the sides of the ear adjacent tothe top or cross-headthereof, in which event the supporting-rods 7 will be correspondinglyshortened in a manner that will be readily understood without furtherdescription or illustration.

From the foregoing description it will be seen that l have provided asimple, reliable, and effective means for catching and holding anelevator-car in case the hoistingcable thereof breaks. The clutch-dogsof the safety appliance do not depend for their operation upon a singleoperating means, but have the assistance of a second device, which alsoopcrates for the same purpose to throw the dogs into engagement with theguides. It will also be seen that by reason of the particularconstruction and relation of the shoes and the combined guide anddouble-faced rack-bar spreading of the guides is rendered impossible,and the shoes are maintained in proper working relation at all times tosaid guides and rack-bars. This also insures the proper alinement of thedogs with the teeth of the rack-bars, so that there can be no failure ofthe dogs to catch in the teeth when they are rocked upon their fulcrumsbythe mechanism tripped or thrown in to operation by the breakage of themain cable.

It will of course be apparent that the safety device hereinabovedescribed is susceptible of changes in the form, proportion, and minordetails of construction, which may accordingly be resorted to withoutdeparting from the principle or sacrificing any of the advantages 0f theinvention.

IOO

IIO

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is-

l. In a safety device for elevator-cars, the combination with the upperstationary crosshead of a car, of a superimposed cross-head movabletoward and away from the stationary cross-head, a pair of dogs at theside of the car arranged upon opposite sides of one of the guides forcoperation therewith, rods connecting said dogs with the movablecrosshead, a counterweight-cable connecting the two cross-heads andauxiliary means coperating with and independently of saidcounterweight-cable for actuating the movable crosshead toward thestationary cross-head upon breakage of the hoisting-cable, substantiallyas described.

2. In a safety device for elevators, an elevator-car having a stationarycross-head, a superimposed cross-head movable toward and away from thestationary cross-head, a pair of dogs located on opposite sides of oneof the guides for cooperation therewith, rods connecting said dogs withthe movable crosshead, a counterweight-cable connecting the movablecross-head with the stationary crosshead, a rod connected to the movablecrosshead and extending downward into the car, and a spring locatedwithin the car connected to said rod and exerting its tension tocoperate with the counterweight-cable draw the rod downward and move theupper crosshead toward the stationary cross-head upon breakage of thecable, substantially as described.

3. In a safety device for elevators, an elevator-car having a stationarycross-head, a

'superimposed cross-head movable toward and away from the stationarycross-head, clutchdogs for engaging the guides at opposite sides G ofthe elevator, rods connecting said dogs with the movable cross-head,counterweight-cables connecting said cross-heads, rods connected to themovable cross head and extending downward into the car, spring-housingsarranged under the car-seats and concealed thereby, and springs arrangedtherein and engaging the lower ends of said rods and acting to draw therods downward and depress the J movable cross-head upon breakage of thecab'le, substantially as described.

4. In a safety device for elevators, an elevator-car having a stationarycross-head, a superimposed cross-head by which the car is suspended,movable toward and away from the stationary cross-head, clutch-dogs onthe car for engagement with the guides at opposite sides of the car,rods connecting said dogs with themovable cross-head, a main cableconnected with the movable cross-head, one or more counterbalance-cablesextending downward past the movable cross-head, under a pulley on thestationary cross-head, and thence upward and attached to the movablecross-head, whereby upon breakage of the cable the counterbalance-cableserves to actuate the movable cross-head toward the stationarycross-head, and auxiliary means cooperating with saidcounterweight-cables,substantially as and for the purpose specified.

5. In a safety device for elevators, the combination with an elevator'car, and guides therefor having teeth along their opposite sides, ofshoes secured to the car and embracing said guides, each of the shoesbeing provided with oppositely located grooves in which the' teeth arereceived, substantially as described.

6. Ina safety device for elevators, the combination with anelevator-car, of guides at the opposite sides thereof, each guidecomprising a double-faced rack-bar and strips or sections of less widtharranged upon the inner and outer surfaces of the rack-bar and bolted orotherwise secured thereto, and shoes se# cured to the car and embracingthe combined guide and double rack-bar, each of said shoes being groovedto receive the teeth of the rackbar and to provide oppositely-locatedshoul ders for engagement with the opposite side faces of the teeth ofthe rack-bar, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN FLnToinrR.y

VVit-nesses:

Jos. F. ECKARD, CHARLES R. ODoNNELL.

